1. Field of Use
The present invention relates to copper-nickel based alloys (hereinafter, it may be referred to as "Cu-Ni based alloys"). More particularly, the present invention relates to Cu-Ni based alloys such as Cu-Ni-Zn alloys, Cu-Ni-Sn alloys, Cu-Ni-Si alloys and Cu-Ni-Al alloys, which are useful for electronic parts.
2. Description of the Background
Heretofore, as the Cu-Ni based alloy, there have been nickel silver or a Cu-Ni-Zn alloy which has been known for a long time, a Cu-Ni-Si alloy which is commonly called as Corson alloy, a Cu-Ni-Sn alloy which utilizes spinodal decomposition, and the like. They have been very much used as material for electronic parts.
The above-mentioned Cu-Ni based alloy was formerlly produced by mold-casting followed by forging, and has been used as expanded material. Recently, continuous casting has been applied thanks for development of technology. However, conventional Cu-Ni based alloys have problems such as their inferior in casting properties, particularly horizontal continuous casting properties.
As the problems in the horizontal continuous casting of the Cu-Ni based alloy as mentioned above, the following drawbacks may be mentioned:
The life of graphite used as mold is very short;
surface texture of ingot during the casting step becomes degraded, whereby commercialization is difficult;
ingot breaks out; and
cracks arise in the first rolling step of ingot.